polars.Expr.struct.field#

Expr.struct.field(name: str) → Expr[source]#

Retrieve a Struct field as a new Series.

Parameters:

name: Name of the struct field to retrieve.

Examples

>>> df = pl.DataFrame(
...     {
...         "aaa": [1, 2],
...         "bbb": ["ab", "cd"],
...         "ccc": [True, None],
...         "ddd": [[1, 2], [3]],
...     }
... ).select(pl.struct(["aaa", "bbb", "ccc", "ddd"]).alias("struct_col"))
>>> df
shape: (2, 1)
┌──────────────────────┐
│ struct_col           │
│ ---                  │
│ struct[4]            │
╞══════════════════════╡
│ {1,"ab",true,[1, 2]} │
│ {2,"cd",null,[3]}    │
└──────────────────────┘

Retrieve struct field(s) as Series:

>>> df.select(pl.col("struct_col").struct.field("bbb"))
shape: (2, 1)
┌─────┐
│ bbb │
│ --- │
│ str │
╞═════╡
│ ab  │
│ cd  │
└─────┘

>>> df.select(
...     pl.col("struct_col").struct.field("bbb"),
...     pl.col("struct_col").struct.field("ddd"),
... )
shape: (2, 2)
┌─────┬───────────┐
│ bbb ┆ ddd       │
│ --- ┆ ---       │
│ str ┆ list[i64] │
╞═════╪═══════════╡
│ ab  ┆ [1, 2]    │
│ cd  ┆ [3]       │
└─────┴───────────┘